1. Field
Embodiments of the present invention generally relate to the field of array structures. More specifically, embodiments of the present invention refer to the application of a titanium nitride (TiN) layer as a sensing layer for array structures with microwells.
2. Background
Electrochemical detection is attractive because it provides high sensitivity, small dimensions, low cost, fast response, and compatibility with microfabrication technologies. These characteristics have led to the development of a variety of sensors based on amperometric, potentiometric, and impedimetric signals, and the assembly of sensors into an array format for chemical, biochemical, and cellular applications. For example, chemically-sensitive field effect transistors (chemFETs) arranged in an array format can be used to monitor biological or chemical processes. Such chemFET arrays can involve detection of analytes in solution and/or detection of a charge bound to a surface coupled to an active region of the chemFET.
In some systems, analytes are distributed among an array of confinement regions, such as microwells, in which each of the confinement regions is coupled to at least one chemFET. Such systems are subject to a host of issues that make highly-sensitive measurements challenging. These issues include, among other things, the impedance characteristics between the microwell and a respective chemFET coupled thereto. For instance, a higher capacitance between the microwell and its respective chemFET affects the quality of output signal collected from the chemFET. Therefore, there is a need to improve the impedance characteristics between the microwell and its respective chemFET.